Need Help: GM 847 Cam
11-16-2011, 11:39 PM
#1
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Need Help: GM 847 Cam Hey guys ive been looking into cams for my car im pretty sure i wanna go with the gm 847. right now my car is an a4 but im going to try to see if i cant sell mine and buy an m6 anyways im wanting 3.73 gears and was wondering what kind of heads would be a good match for the gm 847.
Thanks in advance,
Chance
Thanks in advance,
Chance
11-17-2011, 05:13 AM
#2
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Im running Ai 190cc heads on my car right now with very good results. Le2s would also be another very nice option. As for aftermarket heads like trick flow gen x 21 degree would be nice, And AFR heads would be another good out of the box option.
11-17-2011, 11:25 AM
#3
A good read:
https://ls1tech.com/forums/lt1-lt4-m...ion-guide.html
Understand that to use the 847 properly you need to spin it to 6400-6500 RPM+, beyond what's considered safe for a stock bottom end. At the minimum you'll need to install some ARP rod bolts and resize the big ends of the rods to accomodate the rod bolt change. Driveability may not be what you're looking for in a daily driver. There are smaller duration cams on a 110LSA that will give you the 'sound' you're looking for that make power under 6200 RPM.
https://ls1tech.com/forums/lt1-lt4-m...ion-guide.html
Understand that to use the 847 properly you need to spin it to 6400-6500 RPM+, beyond what's considered safe for a stock bottom end. At the minimum you'll need to install some ARP rod bolts and resize the big ends of the rods to accomodate the rod bolt change. Driveability may not be what you're looking for in a daily driver. There are smaller duration cams on a 110LSA that will give you the 'sound' you're looking for that make power under 6200 RPM.
11-17-2011, 12:41 PM
#4
^ What he said. That's a big cam for a DD and would likely be a pain in the *** to drive regularly and you risk blowing your engine if you spin it to where it makes peak HP. If you do go with it, forget 3.73's with a 6sp....4.10's minimum all the way.
11-17-2011, 01:58 PM
#6
Yea, and a lot of guys blow up the stock bottom end doing so...I did. 
OP do it at your own risk....don't say nobody warned you though. 
You need a forged bottom end to PROPERLY utilize that particular cam's potential without raising serious reliability concerns with the stock shortblock.
11-17-2011, 02:01 PM
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Yea, and a lot of guys blow up the stock bottom end doing so...I did. OP do it at your own risk....don't say nobody warned you though. You need a forged bottom end to PROPERLY utilize that particular cam's potential without raising serious reliability concerns with the stock shortblock.Trending Topics
11-17-2011, 02:42 PM
#11
I would have to agree, that cam is too big for a stock bottom end car to last. But being too big for DD I don’t think so, I have LE cam that is bigger than the GM 847 and I DD mine just fine. Now no way will it drive like a stock cammed car , it will take a change in your driving style.
About the heads, I like my LE2 heads but AI’s are good too
About the heads, I like my LE2 heads but AI’s are good too
11-17-2011, 10:36 PM
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Thanks for all of the advice everyone! its really appreciated i really didnt expect to get this much feedback but i guess you cant ever understimate ls1tech thats why I come here its by far the best. Anyways getting back to the topic right now the car is my dd and ive got a car i got in a trade that im in the works of painting right now then selling/ trading to get a 4wd truck to be my dd. After i get my truck out comes the motor and it will be ready for new paint, new seats, new wheels, new tranny, and suspension. Im really just wanting my car to be an all out show stopper not really a DD. I want something that I can take to car shows, cruise around in with the t tops off ( during spring and the summer of course), something that will put every mustang in its place on the street when they try to race me( which is last of course) 
and when I feel like it slap some slips on it and take it to the track.
and when I feel like it slap some slips on it and take it to the track.
11-17-2011, 11:07 PM
#13
I'm running a cam similiar to the GM 847 and it's a bit of a PITA in traffic. One problem is I'm still running a stock rear with 3.42's the other is too much traffic where I live so I'm probably going to wear out the Spec stage 1 clutch before I even get to the track.
11-18-2011, 05:16 AM
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While the engine is apart are you going to change internals? Like posted by so many above you wont be able to reach the full potential of the 847 with out spinning it fast. Im currently shifting at 6800rpm. You might be better off with a custom grind from Ai or Le to better suit your needs.
11-21-2011, 06:28 AM
#16
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You're on this again? You are one of the few who've blown up doing so. For years and years the answer take a stock shortblock to high rpm has been to change out rod bolts and nothing else. IIRC you still aren't 100% sure what caused your failure.
